Babydoll, sorry for the late reply but I had a thought last night about this problem. Did you by any chance book and/or pay for this cruise on your credit card? Our VISA Platinum (Canadian -don't know about American rules) automatically pays ALL the insurances available on a vacation if the card was used for booking AND final payment. In Canada the agent must, by law, offer insurance at the time of booking. All the agents know which cards cover what LOL!
Please keep us informed of your progress with Carnival. We had a terrible situation with them about 6 years ago and we found that Carnival won't even respond to formal letters or to agent inquiries. We were finally faced with legal action and our lawyer made it quite clear it is nearly impossible to sue an American corporation that doesn't have a Candian "face". We were forced to accept their decision as final and walk away. Needless to say - No Carnival cruises ever again. It would appear you are correct, they are heartless. Once they have your money they don't have to give it back and they won't. Your only recourse is insurance.
It would be interesting to know if anyone on this board ever did get money back directly from any cruise line without resorting to insurance applications.